I just started using 2 turnigy 4000mAh 6s lipos for a single motor shortboard and they work fantastic but I wanted some help figuring out a cheap balance charging plug-and-forget system without a hobby balance charger. I was thinking of using 2 cheap amazon 6s BMS’s and bypassing the over current but didn’t know how if I needed to use a 50.4v charger and put the BMS’s in series or a 25.2v charger with them in parallel. Thanks in advance
You can just hook up one bms to both the batteries and then use a 25.2v charger, otherwise you can also use one bms per battery and hook them up in parralel (so both the C+ and C-) and you can then still use a 25.2v charger, I would not recommend hooking the 2 bms’s in series up 
Hey and maybe you can ask this sort of questions in this thread first before making a whole thread by yourself 
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Are you running the 6s packs in series or in parallel?
If series, then you need a 12s BMS and 50.4v charger, or a 12s balance charger. If parallel, you can just use a single 6s BMS and a 25.2v charger, or a 6s balance charger.
If you’re running parallel, just make up a wiring harness that combines both balance leads together so the BMS can balance both sets of cells.
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I put 2 5s packs in my short board, use a 10s bms only connected to the balance lead (you will need to run a few wires to make this work), discharge through the main leads totally separate from the bms
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I’m running them in series to make 50.4v but I would like to avoid an expensive 12s BMS because I’m just using the balance charging and very simple protection. I would like to use 2 inexpensive 6s BMS’s and was wondering how to connect the charing leads of them.
Ive used a 10s 18650 pack on the same board but it didn’t really have the performance i was looking for so i switched to 12s.
chinese bms’s are super cheap, bms’s usually dont like being run in series
I don’t recommend trying to run multiple BMS’ in series. They’re not designed for that, and may fail or freak out. A 12s BMS doesn’t cost much more than a pair of decent 6s ones will, and I don’t think it’s something worth pursuing to save $10 or so. It’s a bad idea to pinch pennies on something that’s designed to keep your board from catching on fire.
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Any recommendations for a good bms?
tbh i just grabbed the cheapest one on banggood.com, if you are just charging through it it’l probably be fine, but i wouldn’t trust discharging through it
For charge-only, I’d recommend a Bestech D140. They’re about $30. I’ve had a couple of the really cheap banggood ones fail and drain one of the cells down to ~1.5 volts before.
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